I am sure many others have already figured this out, but I was unable to find any sample code with the new alpha channel feature, so thought I would share and hopefully save someone a few minutes (or hours)

"Beginning with version 2011r4, Picture objects support alpha channels (transparency) directly, without the need for a mask.Pictures with alpha channels are supported on Cocoa, Windows (with GDI+ enabled), Linux, console applications, and Web Edition. On platforms without support for alpha channels, a PlatformNotSupported exception is raised when trying to create the Picture."